Zinc supplements shorten the duration of cold symptoms in adults, but not children, according to a meta-analysis of evidence.
Researchers in Canada analysed 17 randomised trials involving 2,121 patients that compared oral zinc treatment with placebo or no intervention.
They found in all age groups zinc significantly reduce the duration of cold symptoms by 1.65 days, compared with placebo or no intervention, but the evidence was of ‘moderate quality’.
In adults, zinc reduced cold symptoms by an average of 2.63 days compared with placebo or no intervention, but only 0.26 days in children – a significant difference.
Study lead Dr Michelle Science, lecturer in infectious diseases at McMaster University, Canada, said: ‘We found moderate quality of evidence to suggest orally administered zinc reduces the duration of symptoms’
CMAJ 2012, online 7 May